In prior art methods for collecting and separating whole blood, a technician places a needle into a vein in the donor's arm, causing whole blood to flow (e.g., by gravity) into a storage bag which may hold a quantity of anticoagulant solution to prevent the collected blood from clotting. After collecting a fixed volume of whole blood (e.g., approximately 400 ml+/−10%) from the donor, the technician removes the needle and the donor is free to leave. The technician then repeats the blood collection step for a number of donors with varying hematocrits (the ratio of the volume of packed red blood cells to the volume of whole blood—typically 38% to 60%). After collecting whole blood from each of the donors, the technician then transports the whole blood bags to a laboratory for processing.
Once in the laboratory, the technician places the whole blood bags into a large centrifuge which spins at a high rate of speed to separate the whole blood within the bags into its constituent components. The technician then removes the bags from the centrifuge (taking care not to re-mix the separated blood components) and transfers the bags to a device such as an expressor to remove plasma from the bag (e.g., leaving red blood cells remaining in the bag). After some additional processing, each of the individual components may then be stored separately.
As one may expect, prior art methods such as those described above are labor intensive, and require numerous manual manipulations. Additionally, because the whole blood must be transported to the lab, the whole blood must be stored for up to several hours prior to processing.